The present invention relates to an apparatus for the preparing or reconditioning the surface of snow skiing courses, or runs, of ski slopes.
The original way of preparing ski runs surfaces consisted of pressing new snow flat by means of rollers. This approach is still used today when sufficient new snow has fallen.
More and more, however, it is necessary to recondition the surfaces of ski runs which have been worn by intensive use. At present, the demand for resurfacing of worn ski runs is about equal to the demand for initial conditioning of runs that have been newly snowed over. This resurfacing is necessary because intensive use of the ski run results at certain locations, particularly on steep run sections, in the formation of an uneven, wavey surfaces having rises and dips. Such a surface requires the less expert skiers to slow down and to execute strenuous avoidance maneuvers.
There is already known a type of apparatus for evening out the irregularities of such uneven ski run sections. One such apparatus includes a driveable chassis provided with a horizontal beam extending the full width of the chassis and carrying a continuous scraper blade at its leading edge. Another has an upright blade provided at the bottom edge with a number of teeth extending to loosen the hard-packed snow of the rises.
The disadvantage of such continuous wide scrapers lies in that they extend over too wide an area to effectively level the relatively small rises. In the course of their forward movement, some portion of the scrapes is likely to strike a rise which raises the scraper at that point and thereby changes the level of the blade along its entire length to prevent it from evenly biting to the desired depth. The result is that other rises at that location are only scraped superficially. The snow thus scraped off settles in the dips between the rises and remains there, usually in the form of hard clumps which are difficult to ski over. It is therefore necessary to work these areas with a further apparatus to loosen and break up the clods and then to pack them down with a roller.
There have been attempts to remedy the disadvantages of these wide scrapers by mounting a number of relatively short scrapers on a frame so that their blades are substantially horizontal and extend in a line across the width. The blades of the scrapers are attached to arms which pivot vertically to permit them to follow the contour of the run surface. A number of relatively wide runners glide side by side in a row in front of the blades. The height of the runners relative to the frame is adjustable. The frame, which is supported in the front on the runners and in the rear on the scraper arms, thus changes its attitude to the surface when the height of the runners is changed. The change in attitude of the frame then results in a change in the pitch of the scraper blades.
It has proved in practice that even this last-described apparatus has major shortcomings. As the runners follow a raised contour, the forward portion of the apparatus becomes raised, thereby changing the pitch of the scraper blades and preventing them from biting in to a sufficient depth. Furthermore, such apparatus likewise leaves the area covered with loose clumps which must again be worked with a further apparatus. So, similar problems arise here also.